The present application relates to methods and systems for monitoring characteristics in a fluid flow path having a filter that is filtering fluid in the path. More particularly the application relates to methods and systems for measuring ΔP (pressure drop) of fluid flowing through a filter in the fluid flow path and then using the measured ΔP, possibly at a normalized state and/or in conjunction with time and/or other data from the system, to diagnose or estimate characteristics of the fluid, the filter, and/or a working component supplied with the fluid. Such characteristics could include an operating condition of the filter, the remaining useful life of the filter, the relative contaminant concentration in the fluid, and/or the remaining useful life of a working component supplied with the fluid.
The methods and systems described herein are particularly useful when applied to fuel filtration systems for diesel engines. A fuel filtration system for a diesel engine usually has one or more filters. A primary purpose of the filtration system is to maintain fuel contamination levels below specified levels to thereby protect the fuel injection system in the engine from contamination.
The amount of contamination removed by a filter or by a plurality of filters can be measured in a variety of ways. For example it can be defined in terms of β—i.e., the time-weighted ratio of the number concentration of particles larger than a certain size upstream of certain filter(s) to the number concentration of particles larger than the same size downstream of the filter(s) under defined multi-pass filter test conditions. However, as will be recognized by those skilled in the art, contamination removal can also be measured by evaluating efficiency, penetration, filtration ratio, etc.
In actual use, a wide range of potential conditions may exist, in terms of contaminant nature and concentration, operable conditions of the filter, and operable conditions of the engine. In particularly demanding applications, special measures are often required, including use of special filters, use of modified service intervals, replacement of engine components, and/or other measures. However, it is often difficult for operators to know when and what special measures are required. In these applications, it is desirable to provide methods and systems for diagnosing or estimating an operable condition of a filter in the filtration system and/or a level of contamination in the fluid. It is further desirable to provide methods and systems for estimating component or system life based on the cleanliness history of the system in order to guide maintenance and replacement schedules. There is also a need for methods and systems that advise operators of the above-noted conditions and further recommend an appropriate response.
Similar needs exist in applications other than diesel engines. Advantageously, the methods and systems described and claimed herein are also useful in any one of a wide variety of applications having a fluid flow path for fuel, oil, lubrication, hydraulics, air, water and/or other fluids including gases and/or liquids.